Since I like WoW games, but sometimes in between pay periods inlay (and instead play on my F2P starter account), a subscription is not an option. In addition, I will be reluctant to access for smaller amounts into my account. Therefore, the game cards are quite practical, poses no problem and quickly ordered and entered. And even wenns should take times longer (often from Amazon) I may be a few days without.
Nevertheless, I find the 60-day solution is not particularly flexible. A Game Card option for 30 and 15 days of would be quite desirable if you take not two whole months at a time to play.
In addition, the packaging is extremely harmful to the environment. The code could also be obtained by e-mail, without plastic card, plastic CD case to the plastic card, and again drumrum plastic wrap, and then wrapped again for the post.
Game is great, but Gamecard solution practical and ecological needs substantial improvement.
ETA: It is worthwhile to look at the price comparison on the UK import version of the Game Card. Was my last sale 4 EUR cheaper.